초록 ▼

A process for enhancing recovery of metals, especially cobalt, from spent hydroprocessing catalysts when the spent catalyst particles are first roasted at between 400° C. and 600° C. and then contacted with a first aqueous solution of ammonia and an ammonium salt to recover nickel, cobalt, molybdenu

A process for enhancing recovery of metals, especially cobalt, from spent hydroprocessing catalysts when the spent catalyst particles are first roasted at between 400° C. and 600° C. and then contacted with a first aqueous solution of ammonia and an ammonium salt to recover nickel, cobalt, molybdenum, tungsten, and vanadium. The once-leached spent hydroprocessing catalysts are again leached by contacting them with a second aqueous solution of ammonium sulfate at a pH of 1 to 4.

대표청구항 ▼

1. A process to extract metals from spent hydroprocessing catalyst particles comprising: (a) roasting said catalyst particles at a temperature in the range of between 400° C. and 600° C.; (b) contacting said roasted catalyst particles with a first aqueous solution of ammonia and ammonium salt;

1. A process to extract metals from spent hydroprocessing catalyst particles comprising: (a) roasting said catalyst particles at a temperature in the range of between 400° C. and 600° C.; (b) contacting said roasted catalyst particles with a first aqueous solution of ammonia and ammonium salt; (c) separating said catalyst particles from said first aqueous solution; (d) contacting said catalyst particles with a second aqueous solution of ammonium sulfate at a pH in the range of from about 1 to 4; and (e) separating said catalyst particles from said second solution. 2. The process of claim 1 comprising the additional step of precipitating metals present in said second solution with hydrogen sulfide as metal sulfide. 3. The process of claim 2 wherein the temperature of said second solution during said precipitation step is from about 25° C. to 100° C. 4. The process of claim 2 comprising roasting said precipitated metal sulfide with fresh spent catalyst in step 1(a). 5. The process of claim 1 wherein said spent hydroprocessing catalysts are supported on alumina. 6. The process of claim 1 wherein said first aqueous solution has a pH maintained in the range of 9.5 to 11 and concentrations of ammonia plus ammonium salt do not exceed 8 molar. 7. The process of claim 1 wherein the pH of said second solution is maintained at between 1.5 and 2.5.